With visibility utilities you have control the visibility, without modifying the display, of elements.

With visibility utilities you have control the visibility, without modifying the display, of elements.
Easily change the vertical alignment of inline, inline-block, inline-table, and table cell elements.
Change the alignment of elements with the vertical-alignment utilities.
These are the classes:- .align-baseline, .align-top, .align-middle, .align-bottom, .align-text-bottom, and .align-text-top as needed.
The navbar is one of the prominent features of Bootstrap sites. A navigation bar is a navigation header that is placed at the top of the page. the navigation bar can extend or collapse, depending on the screen size. A standard navigation bar is created with the .navbar class.
Easily extend form controls by adding text, buttons, or button groups on either side of textual inputs, custom selects, and custom file inputs.